This invention is related to a two component coating composition.
There are a wide variety of two component coating compositions available for finishing substrates. Typically with these compositions, the components are mixed together before application and then the resulting composition is applied by conventional techniques such as spraying and the composition is cured at ambient temperatures or can be cured at elevated temperatures. These compositions are used to refinish automobiles and trucks, paint structures such as bridges and buildings, paint appliances, metal cabinets and the like.
Representative of such compositions are shown in the following patents:
Marion et al. U.S. Pat. No. 4,452,948 issued June 5, 1984. A two component composition is taught in which one component has at least two free hydroxyl groups and a second component has anhydride groups. However, these compositions have a short "pot life" which is the useable time in which the composition can be applied by conventional means such as spraying. Finishes formed from such a composition generally are have poor solvent resistance and are sensitive to moisture. Under high humidity conditions which are common for automobiles and trucks finishes whiten and blister.
Gordon et al. U.S. Pat. No. 4,507,411, issued Mar. 26, 1985 shows a two component composition of a functionalized polymeric component and glycidyl component that in the presence of an amine, alcohol, ketimine, acetal or oxazolidine cures at ambient temperatures. However, the compositions disclosed are not useful for finishes for automobiles and trucks.
European patent application No. 0,123,793 shows a two component composition in which one component has an anhydride ring that is opened with an amine and has a second component that contains glycidyl groups. Finishes formed from such compositions are not useful for automobiles and trucks since the finishes whiten and blister on exposure to high humidity conditions and exhibit recoat lifting when repaired within several days after the finish has been applied.
There is a need for a coating composition that cures at ambient temperatures and provides a high quality finish that is useful as an exterior finish or refinish for automobiles and trucks that has excellent adhesion to the substrate to which it is applied, good outdoor weatherability and humidity resistance and an excellent appearance.